The present invention relates generally to premixes for incorporation into animal feeds. More particularly, the present invention relates to a premix composition including tylosin or a tylosin-based antibiotic agent, to a method for preparing this premix composition, and to an animal feed including this premix composition.
Tylosin and derivatives of tylosin are well known for their antibiotic activity. Effective against many bacteria, they are useful to treat a broad range of infections in animals. Administration of antibiotic agents such as tylosin or tylosin-based antibiotic agents to animals by way of their feeds is highly convenient and cost-effective. Usually, rather than incorporating antibiotic agents directly into the animal feed, the antibiotic agents are formulated into a concentrated premix containing antibiotic agent. This concentrated premix is then processed into animal feed to afford a medicated feed having the desired dose of antibiotic agent.
After their preparation, concentrated premixes are often stored for long periods prior to use. Thus, the long-term stability of the antibiotic agent in the premix is important. Moreover, in the preparation of animal feeds, the premix is subjected to further conditions that can be deleterious to the antibiotic agent. For example, in preparing pelletized feed, the premix including the antibiotic agent is first mixed with an animal feed material. The resulting mixture is processed by a pellet mill, which conventionally includes a steam conditioner. Such steam conditioners inject live steam into the feed mixtures to hydrate starch which is present. Afterwards, the mixture is run through the die of the pellet mill to process the animal feed into a form that is reduced to pellets. Temperatures in both the steam conditioner and the die can range up to about 100.degree. C. Thus, extreme conditions are presented which can deleteriously affect antibiotics present in the feed. Furthermore, once prepared, the medicated animal feed will often be stored in a non-insulated facility such as a barn for later use. Thus, the storage of the animal feed can also result in conditions which cause a decrease in its antibiotic potency.
Tylosin and tylosin-based antibiotics lack long term stability against hydrolysis when in the presence of moisture and/or other components of animal feed. As a result, the stabilization of tylosin and tylosin-based antibiotic agents when incorporated into premixes, and when these premixes are incorporated into animal feeds, is highly important. The present invention addresses this need.